At least some known turbine engines include an air intake portion, a compressor portion, a combustion portion, a turbine portion, and an exhaust portion. Such known turbine engines produce thrust and/or extract energy from a fluid flow by first compressing the intake air within the compressor portion. The compressor portion may include a series of bladed disks to form a multi-stage, axial compressor. Fuel is added to the compressed air, and the mixture is combusted in the combustion portion. The resulting hot, high-pressure gas is then expanded through the turbine portion to extract energy therefrom. The turbine portion may include a series of vanes and bladed disk assemblies, complementarily forming a multi-stage turbine. As hot gases move through the turbine portion, a portion of the hot gases may, if not adequately protected, excessively heat the cavity and casing supporting the vanes, which may reduce the integrity and lifecycle span of the casing. Thus, a need exists for improved thermal management within the turbine portion, and methods for manufacturing the same.